Spinal implants

Abstract

Disclosed are improved spinal implants that are configured to help prevent post-operative migration of the implant. In some embodiments, the implant system includes multi-axial tooth geometry and other geometrical configurations such as but not limited to peripheral curvatures that aid in the prevention of such post-operative migration. Also disclosed are asymmetrical implants having superior and inferior surfaces with different angulations relative to the sagittal midline.

The invention claimed is: 
     
       1. A spinal implant device comprising:
 a body for holding graft material therein, the body comprising: 
 a sagittal midline; 
 a posterior edge and an anterior edge opposite the posterior edge; 
 a superior surface and an inferior surface opposite the superior surface, at least one of the superior surface and the inferior surface comprising a plurality of teeth; 
 wherein the plurality of teeth comprises a first row of outer teeth positioned circumferentially along a peripheral edge of the body and a second row of inner teeth positioned inwardly from the first row of outer teeth; 
 wherein the first row of outer teeth each comprise an outer side and an inner side that meets with the outer side to form an outer tooth edge at a peak of each respective outer tooth, the outer tooth edge of each respective outer tooth configured to contact a vertebral endplate; 
 wherein the first row of outer teeth is positioned circumferentially along the peripheral edge of the body such that the vertebral endplate contacting outer tooth edge of each outer tooth of the first row of outer teeth is not parallel to vertebral endplate contacting outer tooth edges of adjacent teeth of the first row of outer teeth; and 
 wherein the vertebral endplate contacting outer tooth edges of the first row of outer teeth are configured to contact the vertebral endplate to resist migration of the implant in two directions; and 
 wherein the inner teeth of the second row project further from the sagittal midline than an outwardly adjacent outer tooth of the first row of outer teeth. 
 
     
     
       2. The spinal implant device of  claim 1 , wherein the second row of inner teeth each comprise an outer side and an inner side that meets with the outer side to form an inner tooth edge at a peak of each respective inner tooth, the inner tooth edge of each respective inner tooth configured to contact the vertebral endplate;
 wherein the second row of inner teeth is positioned radially such that the vertebral endplate contacting inner tooth edge of each tooth of the second row of inner teeth is not parallel to vertebral endplate contacting inner tooth edges of adjacent teeth of the second row of inner teeth; 
 wherein the inner tooth edges of the second row of inner teeth are configured to resist migration of the implant in two directions; and 
 wherein the outer tooth edges of the first row of outer teeth and the inner tooth edges of the second row of inner teeth together are configured to resist movement and migration of the spinal implant in a medial-lateral axis and an anterior-posterior axis; 
 wherein a slope of the outer side of each outer tooth from the respective tooth edge toward the sagittal midline is less than a slope of the inner side of each respective outer tooth from the respective tooth edge toward the sagittal midline; and 
 wherein a slope of the outer side of each inner tooth from the respective tooth edge toward the sagittal midline is greater than a slope of the inner side of each respective inner tooth from the respective tooth edge toward the sagittal midline. 
 
     
     
       3. The spinal implant device of  claim 2 , further comprising a trough disposed between the first row of outer teeth and the second row of inner teeth, and wherein the slope of the outer side of each respective outer tooth from the respective outer tooth edge toward the sagittal midline is greater than the slope of the inner side of each respective inner tooth from the respective inner tooth edge toward the sagittal midline. 
     
     
       4. The spinal implant device of  claim 2 , wherein the first row of outer teeth slopes to the anterior edge of the body so that the outer side of each outer tooth faces outwardly from the implant toward the anterior edge and forms a perimeter edge of the implant that is configured to limit point contacts between the perimeter edge of the implant and a vertebral endplate. 
     
     
       5. The spinal implant device of  claim 1 , wherein each tooth of the plurality of teeth are configured to avoid point contact with vertebral endplates. 
     
     
       6. The spinal implant device of  claim 2 , wherein the body defines a central opening and wherein the inner side of each tooth of the second row of inner teeth slopes toward and to the central opening. 
     
     
       7. A spinal implant device comprising:
 a body for holding graft material therein, the body comprising: 
 a sagittal midline; 
 a posterior edge and an anterior edge opposite the posterior edge; 
 a superior surface and an inferior surface opposite the superior surface, at least one of the superior surface and the inferior surface comprising a plurality of teeth; 
 wherein the plurality of teeth comprises a first row of outer teeth positioned along a peripheral edge of the body and a second row of inner teeth positioned inwardly from the first row of outer teeth; and 
 wherein a trough separates each tooth of the first row of outer teeth from each tooth of the second row of inner teeth that is inwardly adjacent from each tooth of the first row of outer teeth; 
 wherein each of the outer teeth of the first row of outer teeth comprises an outer side and an inner side that meets with the outer side to form an outer tooth edge at a peak of each respective outer tooth, the outer tooth edge of each respective outer tooth configured to contact a vertebral endplate while avoiding point contact with the vertebral endplate, and wherein a slope of the outer side of each outer tooth from the respective outer tooth edge toward the sagittal midline is less than a slope of the inner side of each respective outer tooth from the respective outer tooth edge toward the sagittal midline; 
 wherein each of the inner teeth of the second row of inner teeth comprises an outer side and an inner side that meets with the outer side to form an inner tooth edge at a peak of each respective inner tooth, the inner tooth edge of each respective inner tooth configured to contact the vertebral endplate while avoiding point contact with the vertebral endplate, and wherein a slope of the outer side of each inner tooth from the respective inner tooth edge toward the sagittal midline is greater than a slope of the inner side of each respective inner tooth from the respective inner tooth edge toward the sagittal midline. 
 
     
     
       8. The spinal implant device of  claim 7 , wherein the first row of outer teeth slopes to the anterior edge of the body so that the outer side of each outer tooth faces outwardly from the implant toward the anterior edge and forms a perimeter edge of the implant that is configured to limit point contacts between the perimeter edge of the implant and a vertebral endplate. 
     
     
       9. The spinal implant device of  claim 7 , wherein the body defines a central opening and wherein the inner side of each of the second row of inner teeth slopes toward and to the central opening. 
     
     
       10. A spinal implant device comprising:
 a body for holding graft material therein, the body having comprising: 
 a sagittal midline; 
 a posterior edge and an anterior edge opposite the posterior edge; 
 a superior surface and an inferior surface opposite the superior surface, at least one of the superior surface and the inferior surface comprising a plurality of teeth; 
 wherein the plurality of teeth comprises a first row of outer teeth positioned along a peripheral edge of the body and a second row of inner teeth positioned inwardly from the first row of outer teeth; and 
 wherein the outer teeth each comprise an outer side and an inner side that meets with the outer side to form an outer tooth edge at a peak of each respective outer tooth, the outer tooth edge of each respective outer tooth configured to contact a vertebral endplate, and wherein a slope of the outer side of each outer tooth from the respective outer tooth edge toward the sagittal midline is less than a slope of the inner side of each respective outer tooth from the respective outer tooth edge toward the sagittal midline; 
 wherein the first row of outer teeth is positioned circumferentially along the peripheral edge of the body such that the vertebral endplate contacting outer tooth edge of each tooth of the first row of outer teeth is not parallel to vertebral endplate contacting outer tooth edges of adjacent teeth of the first row of outer teeth, the vertebral endplate contacting outer tooth edges of the first row of outer teeth being configured to resist migration of the implant in two directions; 
 wherein the inner teeth each comprise an outer side and an inner side that meets with the outer side to form an inner tooth edge at a peak of each respective inner tooth, the inner tooth edge of each respective inner tooth configured to contact the vertebral endplate, and wherein a slope of the outer side of each inner tooth from the respective inner tooth edge toward the sagittal midline is greater than a slope of the inner side of each respective inner tooth from the respective inner tooth edge toward the sagittal midline; 
 wherein the second row of inner teeth is positioned radially such that the vertebral endplate contacting inner tooth edge of each tooth of the second row of inner teeth is not parallel to vertebral endplate contacting inner tooth edges of adjacent teeth of the second row of inner teeth; 
 wherein the vertebral endplate contacting outer tooth edges of the first row of outer teeth and the vertebral endplate contacting inner tooth edges of the second row of inner teeth together are configured to resist movement and migration of the spinal implant in a medial-lateral axis and an anterior-posterior axis. 
 
     
     
       11. The spinal implant device of  claim 10 , wherein the slope of the outer side of each respective outer tooth from the respective outer tooth edge toward the sagittal midline is greater than the slope of the inner side of each respective inner tooth from the respective inner tooth edge toward the sagittal midline. 
     
     
       12. The spinal implant device of  claim 10 , wherein the first row of outer teeth slopes to the anterior edge of the body so that the outer side of each outer tooth faces outwardly from the implant toward the anterior edge and forms a perimeter edge of the implant that is configured to limit point contacts between the perimeter edge of the implant and a vertebral endplate. 
     
     
       13. A spinal implant device comprising:
 a body for holding graft material therein, the body comprising: 
 a sagittal midline; 
 a superior surface and an inferior surface opposite the superior surface, at least one of the superior surface and the inferior surface comprising a plurality of teeth; 
 a posterior edge and an anterior edge opposite the posterior edge, the posterior edge of the body including a first notch and second and third notches adjacent to the first notch on opposite sides of the first notch, the second and third notches configured to limit tissue compression against nerve roots in a vertebral disc space; 
 wherein the plurality of teeth comprises a first row of outer teeth positioned circumferentially along a peripheral edge of the body and a second row of inner teeth positioned inwardly from the first row of outer teeth; 
 wherein each of the outer teeth of the first row of outer teeth comprises an outer side and an inner side that meets with the outer side to form an outer tooth edge at a peak of each respective outer tooth, the outer tooth edge of each respective outer tooth configured to contact a vertebral endplate, and wherein a slope of the outer side from the respective outer tooth edge toward the sagittal midline is less than a slope of the inner side of each respective outer tooth from the respective outer tooth edge toward the sagittal midline; 
 wherein each of the inner teeth of the second row of inner teeth comprises an outer side and an inner side that meets with the outer side to form an inner tooth edge at a peak of each respective inner tooth, the inner tooth edge of each respective inner tooth configured to contact the vertebral endplate, and wherein a slope of the outer side from the respective inner tooth edge toward the sagittal midline is greater than a slope of the inner side of each respective inner tooth from the respective inner tooth edge toward the sagittal midline; 
 wherein the first row of outer teeth is positioned circumferentially along the peripheral edge of the body such that the vertebral endplate contacting outer tooth edge of each outer tooth of the first row of outer teeth is not parallel to vertebral endplate contacting outer tooth edges of adjacent teeth of the first row of outer teeth; and 
 wherein a trough separates each tooth of the first row of outer teeth from each tooth of the second row of inner teeth that is inwardly adjacent from each tooth of the first row of outer teeth, and 
 wherein each tooth of the plurality of teeth is configured to avoid point contact with vertebral endplates; and 
 wherein the vertebral endplate contacting outer tooth edges of the first row of outer teeth and the vertebral endplate contacting inner tooth edges of the second row of inner teeth are configured to contact the vertebral endplate and together are configured to resist movement and migration of the spinal implant in a medial-lateral axis and an anterior-posterior axis; and 
 wherein the inner teeth of the second row project further from the sagittal midline than an outwardly adjacent outer tooth of the first row of outer teeth. 
 
     
     
       14. The spinal implant device of  claim 13 , wherein the slope of the outer side of each respective outer tooth from the respective outer tooth edge toward the sagittal midline is greater than the slope of the inner side of each respective inner tooth from the respective inner tooth edge toward the sagittal midline. 
     
     
       15. The spinal implant device of  claim 13 , wherein the first row of outer teeth slopes to the anterior edge of the body so that the outer side of each outer tooth faces outwardly from the implant toward the anterior edge and forms a perimeter edge of the implant that is configured to limit point contacts between the perimeter edge of the implant and a vertebral endplate.